In the manufacture of electronic circuitry of the type which utilizes circuit boards having discrete devices mounted thereon, it has been found to be highly advantageous to eliminate manual insertion techniques, for the discrete components, and to replace such techniques with automatic insertion techniques. The automatic placement of parts on the circuit board is more desirable, due to the fact that it is cheaper, quicker and substantially error free. Once the desirability of automatic insertion and fastening of discrete components to the circuit board has been decided upon, then the problems associated with the handling of the particular discrete components become acute. Some of the problems are of course the physical design of the components must be such that the fabricating machine can index the component in the correct polarity and/or angular relationship with respect to the conductors on the circuit board, and also in the physical transportation of the component from the parts bin to the circuit board under fabrication. One additional problem is associated with the soldering of the circuit board conductors to the discrete device in order to make a secure electrical contact. Various techniques have been used to achieve the soldering joint, namely, manual techniques, flow soldering, dip soldering, etc. It would be highly desirable to have a discrete electronic component which could be machine insertable into a circuit board without the need for soldering, while still maintaining a highly conductive and contaminent-free electrical contact.
A number of configurations have been proposed for machine-insertable components. In for example, U.S. Pat. No. 2,990,498, entitled "Capacitor" by S. W. Evans, there is disclosed an electronic component which is particularly adaptable to being inserted into a circuit board. More specifically, there is disclosed a capacitor which is trapezoidal in shape and which is formed by a dialectric material having electric plates on either side thereof with the capacitor being inserted edgewise into a rectangular opening in the circuit board.
The plates of the electrical component are soldered to the circuit board to provide the required electrical contact and in addition it appears that some support is provided by the soldered joint. Another patent of interest is U.S. Pat. No. 3,142,783, entitled "Electrical Circuit System" by W. B. Warren wherein there is disclosed a circuit board having a hole drilled therethrough for receiving an electrical component which component is cylindrical in shape. Each end of the cylindrical component, or housing for a component, has an electrical conductor affixed thereto for making contact with electrical conductors on the circuit board. One end of the hole in the circuit board is provided with tabs that project into the open area so as to limit the travel of the component when it is inserted into the circuit board. For the components shown in the subject patent, connection is made by means of welding or soldering the electrical board conductors to the electrical conductors on the component.
Another device of interest is disclosed in U.S. Pat. No. 3,218,584, entitled "Strip Line Connector" by D. R. Ayer. The device disclosed in the subject patent is one which can make contact to a multi-layer printed circuit board. The component is provided with layers and associated contacts which contacts engage corresponding contacts affixed to the circuit board. The board contacts are bent so as to provide a spring action which insures contact when pressure is applied during the insertion of the component.
Another prior art device particularly adaptable for use with a printed circuit board is disclosed in U.S. Pat. No. 3,417,294, entitled "Mounting Circuit Elements in Printed Circuit Boards" by M. Steidlitz. In that patent there is disclosed an electronic component which is cylindrical in shape and which has a segment of the outer cylinder wall forming at least one electrical contact along with a tab which projects from the cylinder wall through an area not covered by the electrical contact forming at least one other electrical connection. Electrical contact between the board electrical conductors and the corresponding conductors on the electrical component is accomplished by compressing the respective layers of the board to cause a compression joint between the electrical conductors.
Another device of interest is disclosed in U.S. Pat. No. 3,480,836, entitled "Component Mounted In A Printed Circuit" by J. Aronstein. In that patent there is provided a circuit board through which an apertured opening is formed having a tab index. An electronic component having an outside diameter which is less than the diameter of the hole is inserted and indexed using a projecting tab within the hole. Electrical conductors on the circuit board project into the hole and are electrically bonded to corresponding conductors on the circuit component. The particular bonding must be individually done in that the circuit board conductors shown are electrically isolated from each other.
In order to minimize the cost and to increase the effectiveness of the automatic machinery used to insert electrical components, it appears highly desirable that the circuit boards contain easily drillable apertures, namely holes, rather than rectangular and/or odd-shaped openings, particularly openings that require key indexing which in turn requires accurate punching and/or milling of the board. In addition, another desirable feature would be that of having the components adaptable for use in a multi-layer board that is, where conductors which are embedded within the board at different layers can also be easily attached to the contacts of the electrical component. Another desirable feature for any automatic mounted component is to enable the component to be inserted into the board using automatic techniques which insertion process also causes the electrical bond normally accomplished by soldering to be made simultaneously with the insertion.